Investigation of the unsaturated acids of cottonseed oil

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In the course of a study of the methods of analysis of cotton seed oil from linoleic acid, by means of the isolation of the acid as its bromine compound, the end product of the analysis which should have been linoleic tetrabromide with a melting point of 113-115 degrees Celsius was instead a white crystalline compound with properties widely different from the linoleic tetrabromide which is described by Lewkowitsch, Hazura, Farnsteiner, etc. The crystals obtained were large needle shaped prism forms arranged in radiating clusters, with a specific gravity much less than that of linoleic tetrabromide. After several purifications from ninety-five percent alcohol, the crystals possessed a definite melting point not 58-58.5 degrees Celsius. The crystals were also much more soluble in ninety-five percent alcohol, glacial acetic acid, petroleum ether and other organic solvents than linoleic tetrabromide and could be crystallized from all these solvents in the same form as obtained from alcohol. It at once became apparent that the body thus obtained was worthy of careful study as a possible means of explaining the wide discrepance between the theoretical percentage of linoleic acid in cottonseed oil and the percentage which has been obtained by actual analysis. The importance of the body was considerably enhanced, also on account of the fact that an isomer of the ordinary linoleic tetrabromide of cottonseed oil has been obtained by Thomas from Telfairia oil, which according to that author gave a tetrabromide with a melting point of 57-58 degrees Celsius. The investigation, which is here reported, was carried out with the purpose of explaining the formation of the unknown compound, its chemical composition, its relation to the isomeric linoleic acid obtained by Thoms, and its relation to the isomeric linolic acid obtained by Thoms, and its relation to the composition of cottonseed oil.